COWBOY UP: Michael Boley, back from a one-game suspension and healed from a hip injury, is expected to add strength to the Giants' weak-side defense this Sunday vs. Dallas.NY Post: Charles Wenzelberg

While his new team was busy preparing for the season opener, Michael Boley was in Arizona, working out, staying in shape.

When his new team was busy disposing of the Redskins, Boley was in New Jersey but not at Giants Stadium. Instead, Boley was at his house, watching on television.

“Very strange,” Boley said yesterday. “I would have to say it’s my first week I’ve been away from football since . . . forever. It was real different. It was tough seeing your teammates flying around, having fun and not being able to be there. It was hard.”

The banishment is over, and Boley is back. He was not allowed to be anywhere around the Giants for the past week and he could not play in Sunday’s 23-17 win as part of the one-game suspension handed down for violating the NFL’s personal conduct policy. Boley last year was involved in a domestic-abuse incident when he was with the Falcons but wasn’t punished until now.

Without Boley — signed to a five-year, $25 million contract to move right in as the starting weak-side linebacker — and two cornerbacks — starter Aaron Ross and valuable reserve Kevin Dockery — the Giants stormed out of the gates on defense. Time will tell whether they are indeed as deep and talented as they appear to be, or the Redskins are that mediocre on offense.

Chase Blackburn started in what is presumed to be Boley’s spot and played well, other than a missed tackle on what turned out to be a 34-yard run by Clinton Portis — his only significant gain all day. Blackburn made up for it on the very next play, not getting fooled for a moment on an attempted option pass by Antwaan Randle El. Blackburn, along with Justin Tuck, chased him down for an 11-yard sack.

Terrell Thomas started in place of Ross and, other than a 35-yard reception for Randle El, handled himself well. Rookie free agent Bruce Johnson was the nickel back in his NFL debut and forced a fumble (out of bounds) from tight end Chris Cooley and made two stops of Portis.

“He made two open field tackles against a good running back,” Antonio Pierce said. “I thought he played very well. Obviously the experts were saying we had secondary problems because we were nicked up.”

Boley’s arrival adds another player the Giants believe can be a difference-maker on the weak side, an area they haven’t exactly prospered since allowing Kawika Mitchell to leave in free agency after the Super Bowl.

Boley missed all of training camp following surgery to repair a torn labrum in his hip. He finally was able to participate in some individual drills last week and then had to leave for his suspension.

Teammates called him “rookie” and “the new guy” when he returned. Boley said he expects for the first time to take part in a full practice tomorrow and sees no reason why he won’t make his Giants debut Sunday against the Cowboys.

“He’s been going through all the mental reps; I think he’s probably mentally drained from that,” Pierce said. “Now we need him physically to make plays for us.”